Preheat your oven to 350°F (175°C) and grease a loaf pan with nonstick cooking spray.
In a small bowl, combine flour, baking powder, baking soda, salt, cinnamon, and nutmeg. Mix these dry ingredients well and then set them aside.
In a larger mixing bowl, combine sugar, oil, eggs, and mashed bananas. Mix everything thoroughly until well blended.
Add the flour mixture to your wet ingredients and mix just until combined. Pour this mixture into your prepared loaf pan.
Place your loaf pan in the preheated oven and bake for about 45–55 minutes. Check doneness by inserting a toothpick into the center.
Once baked, remove the banana bread from the oven and allow it to cool completely before cutting into it.